Problem: Solve for $y$ : $-6 + y = 7$
Answer: Add $6$ to both sides: $ \begin{eqnarray} \\ -6 + y &=& 7 \\ \\ {+6} && {+6} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-6 + y} &\hphantom{=}& \hphantom{7} \\ y &=& 7 {+ 6} \\ \end{eqnarray} $ Simplify. $ y = 13$